Landscape Evolution and Deglaciation of the Upper Peninsula,Michigan: An Examination of Chronology and Stratigraphy in Kettle Lake Cores

We propose a radiometric chronology bracket for the last glacial advance/retreat, called the Marquette readvance, in the Upper Peninsula of Michigan (Upper Peninsula) using organic material from kettle lakes and previously published age determinations on wood buried by glaciofluvial sediments. The lakes are located both inside and outside the ice-contact margin of the Marquette readvance. Wood buried in glaciofluvial sediments from the Marquette readvance was previously dated at 10,025 ± 100 ¹⁴C yr BP (Hughes and Merry 1978, Lowell et al. 1999, and Pregitzer et al. 2000). Ackerman Lake, a kettle lake located inside the ice-contact margin, yielded a basal radiocarbon date of 9,495 ± 70 ¹⁴C yr BP representing the time of organic accumulation after ice retreat. These dates above and below the glacial deposit bracket the age of the Marquette readvance/retreat to 360–700 ¹⁴C yr, or the midpoint of 530 ¹⁴C yr. Ackerman Lake yielded multiple radiocarbon dates, including an average date of 8,811 ± 11 ¹⁴C yr BP (9,736–9,913 cal yr BP) at a change in stratigraphy from red clay to gray silt. This transition along the northern Upper Peninsula is interpreted to represent ice sheet retreat into Lake Superior and the reworking of older glacial sediments by ∼8,500 ¹⁴C yr BP. Organic material from the kettle lake sediments spanning multiple geomorphic locations (both inside and outside of the ice-contact margin) and previous radiocarbon dates from the entire Upper Peninsula yielded dates concentrating around 9,500 ¹⁴C yr BP. We attribute this synchronous organic accumulation in the Upper Peninsula to be a result of climatic signature corresponding with the Preboreal Oscillation, so the duration of the Marquette glacial cover may have been less then implied by the Ackerman Lake basal age.     

The effects of self-attention and public attention on eating in restrained and unrestrained subjects.

Conducted 2 experiments to assess the effects of self-attention and public attention to food intake on eating by dieters and nondieters. In Exp I, in which 96 female undergraduates participated, female dieters ate the greatest number of candies ad lib after consuming a forced 2-milkshake preload; the addition of either self-attention or implied public attention, through the manipulated availability of a wastebasket for the disposing of candy wrappers, inhibited eating substantially. For nondieters, the preload itself inhibited candy consumption, which declined further only under conditions of public attention to candy intake. In Exp II, in which 105 female university students and 3 secondary school students participated, self- and public attention again inhibited the cookie consumption of preloaded dieters, but preloaded nondieters were not influenced by the attention manipulations, eating minimally in all conditions. Nondieters who were not preloaded, however, reduced their intake in the 2 attention conditions. Implications for regulatory self-control were discussed. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)